Question

1,8+7t-10t^2 больше или рано 3

Answer 1

1,8+7t-10t^2 >= 3
1,8+7t-10t^2 -3 >= 0
-10t^2+ 7t - 1.2 >= 0
-10t^2+ 7t - 1.2 = 0
D = 49 - 4*(-10)*(-1.2) = 49 - 48 = 1
t1 = (-7+1)/-20 = 6/20 = 3/10
t2 =  (-7-1)/-20 = 8/20 = 2/5
-10(t-3/10)(t-2/5) >= 0
3/10 <= t <= 2/5

Answer 2

получается ответ 0,1